Background: Despite the well-recognized benefits of running, ultramarathoners exhibit a higher risk of developing various maladaptive outcomes due to psychological factors such as strong motivation for running, a high tolerance for extreme activities, and difficulty adhering to recovery recommendations. Among ultramarathoners, the prevalence of mental health problems is high, including exercise addiction (18.2%), eating disorders (62.5%), sleep disturbances (24.5%), anxiety (12.8%), and depression (18.6%). These disorders rarely occur in isolation, and their coexistence highlights that they interact as a network, playing roles as triggers or amplifiers of each other's symptoms. Purpose: To examine the dynamic association between mental health problems in ultramarathoners runners of both sexes, and to identify which disorder is the trigger point for the development of other mental health issues. Methods: This is a cross-sectional and web-based study. For data collection, we followed the International Olympic Committee Sport Mental Health Assessment Tool 1, including screening for anxiety (GAD-7), depression (PHQ-9), sleep disorder (ASBQ), and additionally about exercise addiction (EAI). Sex, age, body mass, height (to calculate body mass index - BMI), training frequency/week, and competitive level were also obtained. The questionnaire was disseminated through social media, participating race organizers, and running-related platforms. Network analysis was conducted to examine the association between variables, presenting centrality indicators (betweenness and expected influence) for women and men. JASP 0.18.3.0 software was used, and bootstrapping of 1000 resampling was performed. The study was approved by the ethical committee. Results: We sampled 495 ultramarathoners (44.5±8.9 years; 77.3% male) from the five Brazilian macro-regions. For both sexes, the competitive level, age, and training frequency/week were not related to mental disorders. Strong connections were observed between screening positive for anxiety, depression, sleep disorders, and exercise addiction. For women, anxiety (betweenness: 2.47; expected influence: 1.67) was the most central variable in the network, while depression (betweenness: 1.75) and anxiety (expected influence: 1.34) presented the strongest influence for men. These results indicate that both variables can work as trigger variables to connect other disorders within the systems investigated. Bootstrap results demonstrated a good fit to the observed data, especially among men. Conclusion: Anxiety appears to be a primary trigger in the symptom network for both sexes. Preventive strategies should consider screening and monitoring signs of anxiety and depression that may have an impact on other mental health conditions.